How can I switch temporally Linux ASCII console to RS232 port build-in computer. I mean about Linux system working as server, without running any graphical tools on it (X11, bootsplash etc).
But I want to do it temporally just "on demand". In ordinary usage, the console should be normal VGA monitor. Is it possible?

Do you really mean "the console" or are you simply trying to attach a terminal via a serial port? In Unix, the console is one of many ttys, but it hapens to be the one where the pre-boot/boot functionality is configured via, and where some messages are written. Do you need the latter?
–
symcbeanJul 19 '13 at 8:57

1 Answer
1

It's all well documented in the kernel documentation, and in modern distributions it should be sufficient to edit /etc/inittab in order to have a terminal listening on your serial port - which is what I assume you want to do.

If you just want the console messages displayed, edit your boot options accordingy.

OK. I place something like 0:respawn:/sbin/agetty -L ttyS0 -H MEDIA 9600 vt100 but the problem is that /etc/inittab is no longer valid because systemctl is used. So what and where I have to place?
–
mackowiakpJul 19 '13 at 15:57

This would be a different question, and could be solved with minimal research effort, but here goes: bit.ly/13Uz2zi
–
RomanJul 20 '13 at 9:47